Extract OPF metadata from a HTML document
| Port | Description |
| source primary |
| Port | Description |
| result primary |
| Local Name | Namespace URI | Default | Description |
| identifier-id | 'pub-id' | The Note that if the document produced by this step is the first document passed on the
"metadata" port of the px:epub3-pub-create-package-doc step, the value of this option
will become the value of the |